Sleep apnea & dentists' role: are we missing the mark?

Acknowledging this expanding role of dentists in OSA, the American Academy of Sleep Medicine (AASM) and the American Academy of Dental Sleep Medicine (AADSM) [1] strongly recommend a team effort by qualified dentists and sleep physicians to treat OSA patients in the best possible way. Despite such a key inclusive role of dentists in this field, we lack enough information and awareness to tackle OSA cases in dental chairs.  This article focuses on the disease's pathophysiology, its serious health consequences, and how dentists can act first-hand in its diagnosis and management.

Interpreting the global evidence on the disease burden:

Patients undergo disrupted sleep and uneven breathing patterns due to these respiratory episodes. This depletes distinct stages of both non-REM and REM sleep. The effects of OSA extend beyond the sleep cycle. It involves repeated blockages in the upper airway, lowering blood oxygen levels, and increasing carbon dioxide. Research indicates that untreated OSA can cause various issues. These include headaches, worsened epilepsy, asthma exacerbations, hypertension, irregular heartbeats, depression, strokes, chest pain, atrial fibrillation, increased motor vehicle accidents, and congestive heart failure. [2]

Healthy individuals spend one-third of their lives sleeping.[3] So, disruptions in sleep quality can create havoc in all aspects of our daily lives. Regarded as a global health issue, OSA prevalence has been rising over the last 20 years. Research reveals that the OSA prevalence increases with age and weight gain.[4]

Classification of sleep apnea:

Apnea is a full blockage of airways for at least 10 seconds, accompanied by a 2 to 4% decline in arterial oxygen saturation. Sleep apnea is categorized into central, obstructive, or mixed types, with varying degrees of severity. [2]

Central sleep apnea (CSA) is linked to a problem in the central nervous system, causing the chest muscles to not function and resulting in reduced lung oxygen intake.

OSA is a partial or total obstruction of the upper airway during non-REM or REM sleep. Considered the most prevalent form of sleep apnea, OSA disrupts regular sleep patterns. When OSA leads to excessive daytime sleepiness, it's referred to as obstructive sleep apnea syndrome (OSAS).

If both central and obstructive apneas are present in a patient, it's termed mixed sleep apnea.

OSA has three categories, based on the apnea-hypopnea index (AHI). The average number of apneas and hypopneas per hour of sleep is taken into account.

1. 1. Mild OSA (5 to 15 events per hour)
   2. Moderate OSA (15 to 30 events per hour)
   3. Severe OSA (more than 30 events per hour)

Understanding the underlying pathology of OSA:

OSA is a complex sleep disorder with a multifaceted pathophysiology. It revolves around upper airway dynamics, neural control, and the interplay of anatomical and physiological factors. This results in diverse causes for OSA. Here is a list of the major ones.

1. 1. Anatomical variations: To get a hold of the basic OSA etiology, we need to look into the anatomy of the upper respiratory tract first. Individuals with OSA are more likely to have a constricted or collapsed upper airway. Obesity, which causes greater fat deposits around the neck and throat, or physical traits such as a wide tongue, tonsils, or a sunken jaw (micrognathia) can all contribute to this.
   2. Predisposing factors: Retrognathia, high-arched palate, nasal septal deviation, longer anterior facial height, steeper anterior cranial base, inferiorly displaced hyoid bone, long soft palate, tumors, and reduced posterior airway space can all contribute to OSA. Chronic smokers and alcoholics are also at a high risk of suffering from OSA.
   3. Dysfunction of neural control: The central nervous system regulates the muscles involved in breathing. Evidence confirms changes in the brain regulatory processes in OSA, resulting in insufficient activation of upper airway dilator muscles during sleep. This malfunction increases the likelihood of airway collapse.
   4. Infections: Allergic rhinitis and recurrent asthma lead to an inflamed airway- and raise the risk of airway collapse.
   5. Diminished muscle tone: During sleep, there is a physiological reduction in muscle tone across the body. In individuals with OSA, the muscles responsible for opening the upper airway experience an excessive degree of relaxation. This heightened relaxation contributes to the collapse of the airway walls, resulting in airflow obstruction.
   6. Heightened sympathetic stimulation: In OSA, there is escalated activity within the sympathetic nervous system. This heightened activation is a consequence of the repetitive occurrences of low oxygen levels (hypoxia) and elevated carbon dioxide levels (hypercapnia) during periods of airway obstruction.

A multidisciplinary integrative approach to diagnosis:

The pathologies often overlap in OSA patients, making a proper diagnosis challenging for dentists, and that's precisely why expert teamwork is recommended to frame the best possible treatment plan, tailored for each patient.

Key points to keep in mind during OSA diagnosis:

A dentist is often the first point of contact for an OSA patient. This makes it important to have an in-depth diagnostic insight. So, keep an open eye for signs of OSA and if you have a doubt, seek expert advice.  Identifying at-risk patients through regular screenings is the initial step for timely therapy.

Cooperation between general medical practitioners (GMPs) and general dental practitioners is essential. When physicians diagnose OSA and consider oral appliance therapy, they prefer qualified dentists. Dentists with specialized sleep medicine training or experience in oral appliance therapy for OSA are the primary choice.

Medical assessment of OSA in the dental chair consists of 5 pillars- patient history, airway evaluation, diagnostic testing, relevant imaging, and potential collaboration with sleep physicians.

Diagnosing in the dental chair can be tough. Thus, a team approach is advised, involving an oral and maxillofacial surgeon, orthodontist, ENT specialist, and craniofacial surgeon. This ensures optimal therapy for adult OSA patients.

AASM - AADSM clinical practice guidelines for stepwise treatment approach for OSA

1. 1. 1. Sleep physicians should consider prescribing oral appliances for adult obstructive sleep apnea patients intolerant of CPAP or preferring alternate therapy.
      2. When a sleep physician prescribes oral appliance therapy, AASM & AADSM recommend qualified dentists craft custom, titratable appliances, as they outperform non-custom devices by reducing AHI, arousal index, and oxygen desaturation while improving oxygen saturation.
      3. Qualified dentists must oversee oral appliance therapy, monitoring for dental side effects and occlusal changes to enhance patient experience and treatment outcome.
      4. Both dentists and sleep physicians should instruct adult patients using oral appliances to schedule regular follow-up visits.
      5. These 2015 guidelines serve as a roadmap for OSA, elevating professional knowledge, patient outcomes, and healthcare cost-efficiency.

Current approaches for managing the disease in the dental chair:

Treatment options for adult OSA vary based on severity, patient preferences, health status, and the healthcare team's expertise.

1. 1. 1. Lifestyle modifications: For mild cases, lifestyle changes like weight loss, positional therapy, and avoiding alcohol before sleep can help.
      2. Oral appliances: Recommend oral appliances if conservative measures fail and patients seek further treatment. These devices adjust the jaw and tongue position to maintain the airway, beneficial for mild to moderate cases. Research shows they improve sleep and quality of life.
      3. Continuous positive airway pressure (CPAP): CPAP therapy involves wearing a mask that delivers a continuous flow of air to keep the airway open during sleep. This is a commonly prescribed treatment for severe OSA.
      4. Surgery: Consider surgery like uvulopalatopharyngoplasty (UPPP), genioglossus advancement (GA), or maxillomandibular advancement (MMA) for major anatomical adjustments or when other treatments are ineffective.

The way ahead:

The scope of oral appliances in OSA is expanding, but specialized dental sleep medicine training is rare. Not all dentists can competently treat OSA or apply evidence-based practices.[4] The AADSM has addressed this through training programs. More dentists need expertise in managing OSA patients. Thus, making sleep-related disorders a part of the UG curriculum is the need of the hour.[5] With growing evidence of OSA's complex nature and collaborative treatment, the dental fraternity must step up to fill this long-existing gap.

References:

1. 1. 1. Ramar, K., Dort, L. C., Katz, S. G., Lettieri, C. J., Harrod, C. G., Thomas, S. M., & Chervin, R. D. Clinical Practice Guideline for the Treatment of Obstructive Sleep Apnea and Snoring with Oral Appliance Therapy: An Update for 2015: An American Academy of Sleep Medicine and American Academy of Dental Sleep Medicine Clinical Practice Guideline. Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine, 11(7), 773-827. https://doi.org/10.5664/jcsm.4858
      2. Padma A, Ramakrishnan N, Narayanan V. Management of obstructive sleep apnea: A dental perspective. Indian J Dent Res [serial online] 2007 [cited 2023 Aug 25];18:201-9.
      3. Alzahrani, M. M., Alghamdi, A. A., Alghamdi, S. A., & Alotaibi, R. K. (2022). Knowledge and Attitude of Dentists Towards Obstructive Sleep Apnea. International Dental Journal, 72(3), 315-321. https://doi.org/10.1016/j.identj.2021.05.004
      4. Lobbezoo, F., Lavigne, G. J., Kato, T., Aarab, G. (2020). The face of Dental Sleep Medicine in the 21st century. Journal of Oral Rehabilitation, 47(12), 1579-1589. https://doi.org/10.1111/joor.13075
      5. Leigh, C., Faigenblum, M., Fine, P., Blizard, R., & Leung, A. (2021). General dental practitioners' knowledge and opinions of snoring and sleep-related breathing disorders. British Dental Journal, 231(9), 569-574. https://doi.org/10.1038/s41415-021-3573-z

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